Carburetor devices

ABSTRACT

For an internal combustion engine. A main fuel feed circuit has an outlet opening onto an induction pipe in the vicinity of the throat. A fuel regulating butterfly member is mounted downstream of the throat and a starting flap is mounted upstream of the throat. An additional fuel feed device has an outlet which opens onto the induction pipe downstream of and in the vicinity of the flap when the flap is substantially in its induction pipe closing position.

United States Patent 11 1 14 1 Sept. 2, 1975 Sigwald 1 i CARBURETOR DEVICES [75] Inventor: Jacques Sigwald, Taverny, France [73] Assignees: Automobiles Peugeot, Paris; Regie Nationale des Usines Renault, Boulogne-Billancourt, both of France [22] Filed: Apr. 16, 1973 [21] Appl. No: 351,636

[30] Foreign Application Priority Data May 29, 1972 France 72.19179 [52] U.S. Cl. 261/39 R; 261/50 R; 261/69 R [51] Int. Cl. FOZM l/l0; FOZM 1/14 [58] Field of Search 261/39 R, 50 R, 69 R [56] References Cited UNITED STATES PATENTS Kittlcr 261/69 R 3,346,245 10/1967 Mennesson ..26l/69R Primary Emminer-Donald R. Schran Assistant Examiner-Z. R. Bilinsky Attorney, Agent, or FirmBurns, Doane, Swecker & Mathis [57] ABSTRACT For an internal combustion engine. A main fuel feed circuit has an outlet opening onto an induction pipe in the vicinity of the throat. A fuel regulating butterfly member is'mounted downstream of the throat and a starting flap is mounted upstream of the throat. An additional fuel feed device has an outlet which opens onto the induction pipe downstream of and in the vicinity of the flap when the flap is substantially in its induction pipe closing position.

9 Claims, 6 Drawing Figures PATENTED SEP 2 I975 SHEET 1 [IF 3 PATENTEU 2 75 SEZCU 2 OF 3 FIG.3

PATENTEB SEP 2 975 SHEEI30f3 It is current practice to employastarting flapin carburetors intended to sup'ply'ra {mixture of airand petrol or gasole'ne to internal combustion engines so as to facilitate starting'the en'ginc when the latter is-cold. This flap. which may be controlled manually or automatically. is p'lacedin the-induction pipe upstream of the venturi. When thc engine is cold. the flap is in its closing position in which'it allows passage of only a small amount of air. The depression or suction produced in the region of the emulsion'outlet jet located in the vicinity of the throat-thus results in an enrichment of the mixture Whieh'facilitates the starting of the engine. As soon as the engine is'sufficiently warm. the starting flap is brought to-its position of maximum opening where it no longer performs its function. When it is desired to accelerate under'moderate load while the starting flap is still in the neighbourhood of its closing position. the opening of the butterfly member produces a drop in the depression prevailing on the downstream side of the latter. This drop in the depression favours the condensation of a partof thc=petrol or gasolene on the cold wall of the induction pipe where it results in a weakening of the mixture which might result in malfunctionin and even a stalling of the engine.

An object of the invention is to overcome the aforementioned drawback.

The solution propbsed'resides mainly in providing in parallel with the main fuel feed circuit opening onto the vicinity of the throat. an additional fuel feed device opening onto the suction-pipe in the vicinity of the starting flap downstream of the'latter when it is in. or in the vicinity of. its closing position. The additional feed device may comprise a well which is connected to prevailing in theinductionpipedownstream of the butterfly member andlor'in accordance with the temperatureof the cnginccoolihg fluid. Y

The invention will be described in more detail with reference to the accompanying drawings in which the FIGURES rcprcscnt'diagrammatically various cmbodimerits of an improved carburetor according to the invention.

FIG. l is a'vi ew in partial cross-section of a-carburetor device constructed in accordance with the present invention.

H6. 2 is avicw in partial cross-section ofa second cmbodiment'of the inventior'rwhich provides fuel enrichmcntduringacceleration? w 1 FIG. 3 isa vie'vi' lll partial cross-section illustrating a third embodiment c'iftlfe'in'vention which limits fuelcn: richment during idling or lowload."

FIG. 4 is a view in partial cross-section illustrating a fourth embodiment 'of the inicntion which limitsfucl enrichment during idlingorlow load.

gine.

FIG. 5 is a viewin partial cross-section illustrating a fifth embodiment of the invention having a thermostatic device to preclude fuel enrichment in a warm en- FIG. 6 is a view in. partial cross-section illustrating a sixth embodiment of the invention having a thermostatic device to preclude fuel enrichment in a warm engine. j

In these FIGURES. the main parts of a conventional carburetor are designated by the same reference characters. These main parts are the following:

A constant-level float chamber 1.

A casing 2 provided with a venturi 3 defining a throat.

A base 4 in which a fuel mixture butterfly member 5 is journalled.

A cover 6 in which a starting flap 7 is journalled.

A main fuel feed circuit 8 comprising a well 9 connected to the float chamber 1 through a calibrated jet 10, an airjet 11 extended by a spray jet 12 and an emulsion outlet nozzle 13 opening into the casing 2.

According to the invention and as shown in FIG. 1, there is added to the carburetor an additional feed device or complementary feed circuit comprising a well 14 which communicates in its lower part with the chamber 1 through a calibrated jet 15 is provided in its upper part with ajet 16 for the entry of air and is connccted through a passageway 17 to an orifice 18 disposed downstream of the flap 7 when the latter occupies a position in the vicinity of the closing position.

This arrangement operates in the following manner:

When the starting flap 7 occupies its closing position (owing to a manual intervention or owing to the action of a thermostatic device in the known manner) and the butterfly member 5 is in the idling position, there is produced in the region of the emulsion outlet nozzle 13 a depression or suction which enrichens the mixture fed totheenginc. This procedure is well known.

At the sametime. a depression or suction is created inv the upper part of the well 14 but it is attenuated owing to entry of air through the jet 16. The latter is so calibrated that the resulting depression brings the level of the fuel slightly below the passageway 17 as shown in FIG. 1. Consequently, the complementary fuel feed circuit does not operate in this stage of operation of the carburetor.

On the other hand, if the flap 7 still in its closed or practically closed position and if the user desires to accelerate the engine by opening the butterfly member 5,

there is produced simultaneously a drop in the depression downstream of the butterfly member 5 and an increase in the depression between the butterfly member 5 and the flap 7. The fuel contained in the well 14 is then drawn in by way of the passageway 17 at the same time as air is drawn in by way of the jet 16. The flow of fuel is controlled by the jet 15..Thus under these conditions of operation. there is a supplementary enrichment whereby it is possible to compensate for the condensation which may occur along the still-cold induction pipe so as to avoid stalling of the engine if the latter is under moderate load.

When the engine has reached a sufficient temperature and the flap 7 has been shifted to a position downstream ofthe orifice l8 by a manual action or an action exertcdby a thermostatic device. the depression prevailingin the well 14 becomes very low and consequently the complementary circuit is put out of action and remains out of action irrespective of the conditions under which the engine is fed with fuel.

in the embodiment shown in FIG. 2, which is slightly more perfected. the elements already shown in FIG. I carry the same reference characters. The improvement resides in the provision of a tube 19 which extends the jet l6 downwardly into the fuel. This tube I9 is provided with a calibrated orifice 20 in its upper part.

This embodiment operates in the following manner: when the flap 7 occupies its closing position and the butterfly member 5 is in its idling speed position. there is created between these two elements a depression which. as in the first embodiment. enrichens the mixture supplied and acts on the upper part of the well H where it is attenuated owing to the entry of air by way of the jet l6 and the orifice 20. The fuel therefore rises in the well to a level slightly below the passageway 17 as shown in FIG. 2.

When the flap 7 is still in a position in the vicinity of the closing position, if it is desired to accelerate the engine by opening the butterfly member 5, fuel is drawn through the passageway 17 but a certain fraction of fuel thus admitted roughly corresponding to the volume initially located above the base of the tube 19., is practically not emulsified owing to the small size of the orifice 20 which allows through very little air. It is only when this first quantity of fuel has been used that the normal mixture is produced owing to the passage of the air by way of the base of the tube 19.

It can be seen that this arrangement, which possesses moreover all the advantages of the first embodiment. also permits obtaining an additional increase in the enrichment at the beginning of the acceleration.

FlGS. 3-6 illustrate additional arrangements for preventing in a certain manner the additional fuel feed when the latter is undesirable.

Thus. with reference to FIGS. 1 and 2, it might be delicate to calibrate exactly the air jets l6 and 20. If they are calibrated too small there is a risk of producing an excessive depression in the upper part of the well l4 and feeding without reason fuel by way of the orifice 18. On the other hand. if they are calibrated too large. the priming time of the device is too long and this renders it inoperative.

FIGS. 3 and 4 illustrate two devices which overcome this drawback and prevent operation of the additional fuel feed device when the engine is employed at idling speed or at low load.

In the embodiment shown in FIG. 3. a capsule 21 mounted in the upper part of the well 14 comprises an elastic diaphragm 22 which divides it into two chambers 21a. 21b. The chamber 21a is connected to the induction pipe. downstream of the butterfly member 5. and receives a spring 23 which biases the diaphragm 22. The chamber 21/) is connected to the atmosphere and communicates by way of an orifice 24 with the upper part of the well 14. The diaphragm 22 carries a closure member 2211 which controls the opening or closing of the orifice 24.

So long as the butterfly member 5 occupies a position in the neighbourhood of closing position. for example the position corresponding to idling speed or low load. the depression acting on the diaphragm 22 maintains it remote from the orifice 24. The depression then prc- \ailing in the upper part of the well 14 is low and the fuel cannot reach the level of the conduit or passage way 17. ll the butterfly member 5 is sufficicntly open.

there occurs a drop in the depression in the induction pipe and the spring 23 biases the diaphragm 22 to close the orifice 24, There is then a sudden increase in the depression in the upper part of the well l4 and a rapid intervention of the additional fuel feed device.

In the embodiment shown in FIG. 4. a capsule 25 comprises an elastic diaphragm 26 subjected to the action of a spring 27 and to the depression prevailing in the induction pipe downstream of the butterfly member 5. This diaphragm actuates a slide 28 placed across the passageway 17. So'long as the butterfly member 5 occupies a position in the neighbourhood of the closing position. the depression acting on the diaphragm 26 is such that the slide 28 closes the passageway 17. On the other hand. if thebutterfly member 5 is sufficiently open. there is a drop in the depression and the spring 27 shifts the diaphragm 26 and slide 28 which opens the passageway 17 as shown in the drawing. The additional fuel feed device can then normally come into operation.

It might also be feared. when the motor is warm. that there accidentally occur in the upper part of the well 14 such depression that the fuel reaches the orifice l8 prematurely.

This may be avoided by employing a thermostatic device precluding in all cases intervention of the additional fuel feed device when the engine is warm. 'l'wo embodiments of such devices are shown in FIGS. 5 and 6.

In the embodiment shown in FIG. 5. a thermostatic element 30 of known type is responsive to the temperature of the engine-cooling water 3,. The finger member 301: of this thermostatic element acts on a valve 32 which controls an orifice 33 for entry of air to the upper part of the well 14. When the temperature of the water is sufficient. the valve 32 opens the orifice 33 and there cannot occur in the upper part of the well 14 a depression which would be sufficient to allow the fuel to reach the passageway 17.

In the embodiment shown in FIG. 6. a thermostatic element 35 is still subjected to the temperature of the engine-cooling water 36. Its finger member 3511 is here employed as a closure member for the passageway 17. When the temperature of the water is sufficient. the passageway 17 is closed and thus renders the additional fuel feed device inoperative.

It is possible. according to needs. to employ solely one of the devices just described. It is also possible to employ both a device responsive to the depression and a device responsive to the temperature by combining. for example. the various arrangements shown in the Figures. Likewise. the improvements disclosed may also be applied to various types of carburetors without departing from the scope of the present invention.

I claim:

I. A carburetor structure for an internal combustion engine comprising means defining an induction pipe. at

throat in the induction pipe. a carburetor float chamher. a main fuel feed circuit having an outlet opening into the induction pipe in the vicinity of the throat and a fuel inlet communicating with the float chamber and an air inlet. a fuel-air mixture regulating butterfly member disposed downstream of the throat with respect to the direction of the flow of the fuel mixture in the induction pipe. an engine starting flap located upstream of the throat with respect to said flow and movable b'etwecn a first position for opening the induction pipe and a second position for substantially closing the induction pipe, an additional fuel feed device comprising a closed fuel well which has a lower part in communication with the float chamber and an upper end in the vicinity of which upper end the well comprises an air inlet and a fuel outlet opening onto the induction pipe downstream of the starting flap with respect to said flow and in the vicinity of the starting flap when the starting flap is substantially in said second position, said air inlet of the well comprising an open-ended air inlet tube for connection to air which tube extends downwardly in the well from adjacent said upper end of the well to below said fuel outlet and defines an orifice which is located in an upper part of the well and puts the interior of the inlet tube in communication with the upper part of the well.

2. A carburetor structure as claimed in claim 1, wherein the well communicates with the float chamber through a calibrated orifice and the air inlet tube has a calibrated air inlet orifice.

3. A carburetor structure as claimed in claim 1, comprising means associated with the additional fuel feed device for neutralizing the additional fuel feed device under predetermined conditions of operation of an engine for which the carburetor structure is intended, the neutralizing means comprising an orifice for communication with outside air located in the upper part of the well, a closure member for selectively opening and closing said air communication orifice. a diaphrahm operatively connected to the closure member, means for subjecting the diaphragm to opposing actions of the depression prevailing in the induction pipe downstream of the butterfly member and of a resiliently yieldable return means.

4. A carburetor structure as claimed in claim 1, said fuel outlet of the well comprising a conduit connecting the well to the induction pipe, means being associated with the additional fuel feed device for neutralizing the additional fuel feed device under predetermined conditions of operation ofan engine for which the carburetor structure is intended. the neutralizing means comprising a closure member inserted in the conduit for selectively opening and closing the conduit. a diaphragm operatively connected to the closure member for actuating the closure member, means for subjecting the diaphragm to opposing actions of the depression prevail ing in the induction pipe downstream of the butterfly member and of a resiliently yieldable return means.

5. A carburetor structure as claimed in claim 1, comprising means associated with the additional fuel feed device for neutralizing the additional fuel feed device under predetermined conditions of operation of an engine for which the carburetor structure is intended. the neutralizing means comprising an orifice for communication with outside air located in the upper part of the well, a closure member for selectively opening and closing said air communication orifice and a thcrmothe well to the induction pipe. means being associated with the additional fuel feed device for neutralizing the additional fuel feed device under predetermined conditions of operation of an engine for which the carburetor structure is intended, the neutralizing meanscomprising a closure member inserted in the conduit for selectively opening and closing the conduit, and a thermostatic element operatively connected to the closure member for shifting the closure member in response to variations in the temperature of cooling fluid for the engine for which the carburetor structure is intended.

7. A carburetor structure for an internal combustion engine comprising means defining an induction pipe, a throat in the induction pipe, a carburetor float chamher, a main fuel feed circuit having an outlet opening into the induction pipe in the vicinity of the throat and a fuel inlet communicating with the float chamber and an air inlet, a fuel-air mixture regulating butterfly member disposed downstream of the throat with respect to the direction of the flow of the fuel mixture in the induction pipe, an engine starting flap disposed upstream of the throat with respect to said flow and movable between a first position for opening the induction pipe and a second position for substantially closing the induction pipe, an additional fuel feed device comprising a closed fuel well which has a lower part in communication with the float chamber and an upper end in the vicinity of which upper end the well comprises an air inlet and a fuel outlet opening onto the induction pipe downstream of the starting flap with respect to said flow and in the vicinity of the starting flap when the starting flap is substantially in said second position, said air inlet of the well comprising an open-ended air inlet tube for connection to air which tube extends downwardly in the well from adjacent said upper end of the well to below said fuel outlet and defines an orifice which is located in an upper part of the well and puts the interior of the inlet tube in communication with the upper part of the well, and means associated with the additional fuel feed device for'neutralizing theadditional fuel feed device under predetermined conditions of operation of an engine for which the carburetor structure is intended.

8. A carburetor structure as claimed in claim 7, wherein said neutralizing means are adapted to be responsive to the depression prevailing in the induction pipe downstream of the butterfly member.

9. A carburetor structure as claimed in claim 7, wherein said neutralizing means are adapted to be responsive to the temperature of the engine-cooling fluid. 

1. A CARBURETOR STRUCTURE FOR AN INTERNAL COMBUSTION ENGINE COMPRISING MEANS DEFINING AN INDUCTION PIPE, A THROAT IN THE INDUCTION PIPE, A CARBURETOR FLOAT CHAMBER, A MAIN FUEL FEED CIRCUIT HAVING AN OUTLET OPENING INTO THE INDUCTION PIPE IN THE VICINITY OFTHE THROAT AND A FUEL INLET COMMUNICATING WITH THE FLOAT CHAMBER AND AN AIR INLET, A FUEL-AIR MIXTURE REGULATING BUTTERFLY MEMBER DISPOSED DOWNSTREAM OF THE THROAT WITH RESPECT TO THE DIRECTION OF THE FLOW OF THE FUEL MIXTURE IN THE INDUCTION PIPE, AN ENGINE STARTING FLAP LOCATED UPSTREAM OF THE THROAT WITH RESPECT TO SAID FLOW AND MOVABLE BETWEEN A FIRST POSITION FOR OPENING THE INDUCTION PIPE AN A SECOND POSITION FOR SUBSTANTIALLY CLOSING THE INDUCTION PIPE, AN ADDITIONAL FUEL FEED DEVICE COMPRISING A CLOSED FUEL WELL WHICH HAS A LOWER PART IN COMMUNICATION WITH THE FLOAT CHAMBER AND AN UPPER END IN THE VICINITY OF WHICH UPPER END THE WELL COMPRISES AN AIR INLET AND A FUEL OUTLET OPENING ONTO THE INDUCTION PIPE DOWNSTREAM OF THE STARTING FLAP WITH RESPECT TO SAID FLOW AND IN THE VICINITY OF THE STARTING FLAP WHEN THE STARTING FLAP IS SUBSTANTIALLY IN SAID SECOND POSITION, SAID AIR INLET OF THE WELL COMPRISING AN OPEN-ENDED AIR INLET TUBE FOR CONNECTION TO AIR WHICH TUBE EXTENDS DOWNWARDLY IN THE WELL FROM ADJACENT SAID UPPER END OF THE WELL TO BELOW SAID FUEL OUTLET AND DEFINES AN ORIFICE WHICH IS LOCATED IN AN UPPER PART OF THE WELL AND PUTS THE INTERIOR OF THE INLET TUBE IN COMMUNICATION WITH THE UPPER PART OF THE WELL.
 2. A carburetor structure as claimed in claim 1, wherein the well communicates with the float chamber through a calibrated orifice and the air inlet tube has a calibrated air inlet orifice.
 3. A carburetor structure as claimed in claim 1, comprising means associated with the additional fuel feed device for neutralizing the additional fuel feed device under predetermined conditions of operation of an engine for which the carburetor structure is intended, the neutralizing means comprising an orifice for communication with outside air located in the upper part of the well, a clOsure member for selectively opening and closing said air communication orifice, a diaphrahm operatively connected to the closure member, means for subjecting the diaphragm to opposing actions of the depression prevailing in the induction pipe downstream of the butterfly member and of a resiliently yieldable return means.
 4. A carburetor structure as claimed in claim 1, said fuel outlet of the well comprising a conduit connecting the well to the induction pipe, means being associated with the additional fuel feed device for neutralizing the additional fuel feed device under predetermined conditions of operation of an engine for which the carburetor structure is intended, the neutralizing means comprising a closure member inserted in the conduit for selectively opening and closing the conduit, a diaphragm operatively connected to the closure member for actuating the closure member, means for subjecting the diaphragm to opposing actions of the depression prevailing in the induction pipe downstream of the butterfly member and of a resiliently yieldable return means.
 5. A carburetor structure as claimed in claim 1, comprising means associated with the additional fuel feed device for neutralizing the additional fuel feed device under predetermined conditions of operation of an engine for which the carburetor structure is intended, the neutralizing means comprising an orifice for communication with outside air located in the upper part of the well, a closure member for selectively opening and closing said air communication orifice and a thermostatic element operatively connected to the closure member for shifting the closure member in response to variations in the temperature of cooling fluid for the engine for which the carburetor structure is intended.
 6. A carburetor structure as claimed in claim 1, said fuel outlet of the well comprising a conduit connecting the well to the induction pipe, means being associated with the additional fuel feed device for neutralizing the additional fuel feed device under predetermined conditions of operation of an engine for which the carburetor structure is intended, the neutralizing means comprising a closure member inserted in the conduit for selectively opening and closing the conduit, and a thermostatic element operatively connected to the closure member for shifting the closure member in response to variations in the temperature of cooling fluid for the engine for which the carburetor structure is intended.
 7. A carburetor structure for an internal combustion engine comprising means defining an induction pipe, a throat in the induction pipe, a carburetor float chamber, a main fuel feed circuit having an outlet opening into the induction pipe in the vicinity of the throat and a fuel inlet communicating with the float chamber and an air inlet, a fuel-air mixture regulating butterfly member disposed downstream of the throat with respect to the direction of the flow of the fuel mixture in the induction pipe, an engine starting flap disposed upstream of the throat with respect to said flow and movable between a first position for opening the induction pipe and a second position for substantially closing the induction pipe, an additional fuel feed device comprising a closed fuel well which has a lower part in communication with the float chamber and an upper end in the vicinity of which upper end the well comprises an air inlet and a fuel outlet opening onto the induction pipe downstream of the starting flap with respect to said flow and in the vicinity of the starting flap when the starting flap is substantially in said second position, said air inlet of the well comprising an open-ended air inlet tube for connection to air which tube extends downwardly in the well from adjacent said upper end of the well to below said fuel outlet and defines an orifice which is located in an upper part of the well and puts the interior of the inlet tube in communication with the upper part of the well, and means associated with the additional fuel feed deVice for neutralizing the additional fuel feed device under predetermined conditions of operation of an engine for which the carburetor structure is intended.
 8. A carburetor structure as claimed in claim 7, wherein said neutralizing means are adapted to be responsive to the depression prevailing in the induction pipe downstream of the butterfly member.
 9. A carburetor structure as claimed in claim 7, wherein said neutralizing means are adapted to be responsive to the temperature of the engine-cooling fluid. 